Air bag with pressurization space

ABSTRACT

An air bag includes two inner sheets facing each other, two outer sheets located at an outer side of the two inner sheets, heat resistance material located at an inner side of any one inner sheet, a first thermal bonding line thermally bonding the two outer sheets to form air input channel, a second thermal bonding line thermally bonding the inner and outer sheets along the material with gap from the first thermal bonding line, and third thermal bonding lines extending from the second thermal bonding line oppositely to the air input channel to form air pillars, a second thermal bonding portion being formed to cross the third thermal bonding lines to thermally bond the two inner and outer sheets to form a pressurization space between the second thermal bonding portion and line, and the second thermal bonding portion being spaced apart from adjacent second thermal bonding portion to form a second passage.

TECHNICAL FIELD

This disclosure relates to an air bag, and more particularly to an airbag with an excellent sealing property by forming a pressurization spacein an air pillar, where a valve is positioned, to press an inner sheet,thereby pressing the valve doubly.

BACKGROUND ART

During delivery of household necessaries or other important articles,the contents are wrapped by an air bag so as to prevent the contentsfrom being broken by external impacts.

In the appended drawings, FIG. 1 is a perspective view showing a generalair bag, and FIG. 2 is a vertical sectional view taken along the lineA-A′ of FIG. 1, which shows a valve of the air bag shown in FIG. 1.

As shown in FIG. 1, the air bag 10 has a valve 20 that is closed by aninner pressure of air injected into the air bag.

The air bag 10 has a rectangular structure, and an air input channel 11is formed along one side of the air bag 10. Also, a plurality of airpillars 13 are perpendicularly formed with respect to the air inputchannel 11. A plurality of valves 20 respectively connect the air inputchannel 11 to the air pillars 13, so air supplied through the air inputchannel 11 is introduced to each air pillar 13 through the valves 20. Ifthe air pillars 13 are filled with air, inner pressure is generated topress the valves 20, thereby sealing the air pillars 13 such that theair in the air pillars 13 does not go out through the valves 20.

Referring to FIGS. 1 and 2, the air bag mentioned above is explained inmore detail. The air bag 10 includes two outer sheets 15 that form anoverall configuration of the air bag. Also, the valve 20 includes twoinner sheets 21 positioned inside the two outer sheets 15 anddiscontinuous heat resistance inks 23 applied to any one of facingsurfaces of the two inner sheets 21, and the valve is formed by aplurality of thermal bonding lines 31, 32, 33, and thermal bondingpoints 41, 42. In FIG. 1, the heat resistance inks 23 applied to aninner side of the inner sheets 21 is depicted as a dotted line.

In a state that the two inner sheets 21 are positioned in the two outersheets 15, the air input channel 11 is formed by a first thermal bondingline 31 and a second thermal bonding line 32, positioned in parallelwith each other. At this time, the second thermal bonding line 32 isformed while passing the heat resistance inks 23 discontinuously formedalong the inner sheets 21. Also, the first thermal bonding line 31 bondsjust the two outer sheets 15.

The air input channel 11 is formed along the first thermal bonding line31 and the second thermal bonding line 32 as mentioned above, and oneside of the air input channel 11 is closed and the other side is opened.Air is injected through the other side that is open.

The outer sheet 15 and the inner sheet 21 are bonded by the secondthermal bonding line 32, but regions where the heat resistance inks 23are formed are not bonded. Thus, the air injected through the air inputchannel 11 is introduced to the air pillars 13 through passages 25between the inner sheets 21, which are not thermally bonded because ofthe heat resistance inks 23.

In addition, the air pillars 13 are formed by third thermal bondinglines 33 extending perpendicularly from the second thermal bonding line32, but the third thermal bonding lines 23 are alternately formed withthe passages formed by the heat resistance inks 23. The air introducedto the air pillar 13 through the passage 25 fills the air pillar 13formed by the third thermal bonding line 33.

Meanwhile, in a region of the two inner sheets 21 positioned toward theair input channel 11 with respect to the second thermal bonding line 32,one inner sheet 21 and one outer sheet 15 are bonded and fixed to eachother by means of the first thermal bonding point 41. As the two outersheets 15 are expanded due to the injected air, the inner sheets 21respectively bonded and fixed by the first thermal bonding point 41become wider in opposite directions to open the passage 25.

However, the two inner sheets 21 positioned toward the air pillar 13with respect to the second thermal bonding line 32 are bonded and fixedto any one outer sheet by the second thermal bonding point 42 to closethe valve 20 by the air filled in the air pillar 13.

Thus, the passages 25 are closed due to the inner pressure of the airpillars 13.

In such a general air bag, when air is injected to the air input channel11, the air is introduced to the air pillar 13 through the passage 25.After the air filled in the air pillar 13 is introduced between theinner sheet 21 and the outer sheet 15, the air presses the two innersheets 21 to close the passage 25.

In such a sealing method, a greater pressure is applied to a curvedregion of the outer sheet 15, which is thermally bonded, such as aregion below the second thermal bonding line 32, than a flat region ofthe expanded outer sheet. It is because the curved region has a largersurface area than the flat portion, so pressure is more greatly appliedto the curved region. Thus, sealing is more excellent as there are morecurved regions. However, the general air bag has only one curved regionto which pressure is greatly applied, namely the region below the secondthermal bonding line, so it does not have a good sealing property.

DISCLOSURE Technical Problem

The disclosure is designed to solve the above problems, and thereforethe disclosure is directed to providing an air bag having an improvedsealing property by forming a pressurization space such that air is notleaked, thereby sealing the air doubly.

Technical Solution

In one aspect, there is provided an air bag, which includes two innersheets positioned to face each other, two outer sheets respectivelylocated at an outer side of the two inner sheets, a heat resistancematerial located at an inner side of the two inner sheets and applied toany one of the inner sheets, a first thermal bonding line for thermallybonding the two outer sheets to form an air input channel, a secondthermal bonding line for thermally bonding the inner sheets and theouter sheets along the heat resistance material with a gap from thefirst thermal bonding line, and third thermal bonding lines extendingfrom the second thermal bonding line in a direction opposite to the airinput channel to form air pillars, wherein a second thermal bondingportion is formed at the third thermal bonding lines in a crossingdirection thereof to thermally bond the two inner sheets and the twoouter sheets such that a pressurization space is formed between thesecond thermal bonding portion and the second thermal bonding line, andthe second thermal bonding portion is spaced apart from a second thermalbonding portion extending from another adjacent third thermal bondingline to form a second passage.

Also, in one embodiment, fourth thermal bonding lines with a lengthsmaller than an interval between the third thermal bonding lines mayextend from the third thermal bonding lines in a lateral direction, andthe fourth thermal bonding lines may thermally bond the two inner sheetsto any one of the outer sheets, and the fourth thermal bonding lines maybe formed at an opposite side to the second thermal bonding line withrespect to the second thermal bonding portion.

Also, in one embodiment, the heat resistance material may becontinuously applied to the inner sheets in a length direction, and thesecond thermal bonding line may thermally bond the inner sheets and theouter sheets along the heat resistance material.

Also, in one embodiment, a plurality of first thermal bonding portionsmay be formed in the air input channel in correspondence to the thirdthermal bonding lines, respectively, such that adjacent first thermalbonding portions are spaced apart from each other to form a firstpassage, and a part of the first thermal bonding portions may thermallybond the two outer sheets and the other part of the first thermalbonding portions may thermally bond the outer sheets to the innersheets.

Also, in one embodiment, at least one thermal bonding point forthermally bonding the two outer sheets in a direction perpendicular tothe air pillars may be formed at a middle of each air pillar in a lengthdirection thereof.

Also, in one embodiment, both ends of the air input channel may beclosed, and a cock may be formed at any one of the outer sheetscorresponding to the air input channel.

ADVANTAGEOUS EFFECTS

As described above, the air bag disclosed herein exhibits an excellentdurability since the air filled in an air pillar is sealed doubly tominimize air leakage.

In addition, the air bag disclosed herein is less restricted inlocations of thermal bonding lines and points since a heat resistanceink is applied over the entire length of a valve, which ensures easierwork, thereby improving productivity and lowering an inferiority rate.

DESCRIPTION OF DRAWINGS

The above and other aspects, features and advantages of the disclosedexemplary embodiments will be more apparent from the following detaileddescription taken in conjunction with the accompanying drawings inwhich:

FIG. 1 is a perspective view showing a general air bag;

FIG. 2 is a vertical sectional view taken along the line A-A′ of FIG. 1,which shows a valve of the air bag shown in FIG. 1;

FIG. 3 is a plan view showing one embodiment of an air bag disclosedherein;

FIG. 4 is a perspective view showing one embodiment of an air bagdisclosed herein;

FIG. 5 is a vertical sectional view taken along the line C-C′, whichillustrates a valve while and after the process of injecting air to theair bag shown in FIG. 4 is executed;

FIG. 6 is a perspective view showing another embodiment of an air bagdisclosed herein;

FIG. 7 is a sectional view taken along the line B-B′, which illustratesexpansion of an air introduction channel and widening of a first passageby the thermal bonding portion shown in FIG. 6; and

FIG. 8 is a plan view showing another embodiment of an air bag disclosedherein, to which a cock is mounted.

REFERENCE NUMERALS OF ESSENTIAL PARTS IN THE DRAWINGS

100: air bag 101: air input channel 103: air pillar 105: outer sheet120: valve 121: inner sheet 140: heat resistance ink 125A: first passage125B: second passage 131-134: thermal bonding line 151, 152: thermalbonding portion 139: thermal bonding point 160: pressurization space170: cock

BEST MODE

Hereinafter, preferred embodiments of the present invention will bedescribed. While the present invention is described with reference toembodiments thereof, the technical idea and the construction andoperation of the invention are not limited to the embodiments.

FIG. 3 is a plan view showing one embodiment of an air bag disclosedherein, and FIG. 4 is a perspective view showing one embodiment of anair bag disclosed herein.

As shown in FIGS. 3 and 4, an air bag 100 of this embodiment includestwo outer sheets 105 (see FIG. 5), two inner sheets 121 (see FIG. 5)that forms a valve 120, and a first thermal bonding line 131 and asecond thermal bonding line 132 that form an air input channel 101.Also, the air bag of this embodiment includes a third thermal bondingline 133 perpendicularly extending from the second thermal bonding line132 to form an air pillar 103, a fourth thermal bonding line 134 forelongating a passage of air passing through the valve 120 to improvesealing, and a second thermal bonding portion 152 for forming apressurization space 160 between the second thermal bonding portion 152and the second thermal bonding line 132. The air bag of this embodimentalso includes a heat resistance ink 140 applied to any one of facingsurfaces of the two inner sheets 121. The heat resistance ink 140 isdepicted as a dotted line in FIGS. 3 and 4.

In a region of the two inner sheets 121 positioned toward the air inputchannel 101 with respect to the second thermal bonding line 132, oneinner sheet 121 and one outer sheet 105 are bonded and fixed to eachother by means of the first thermal bonding point 141.

Here, the fourth thermal bonding lines 134 are formed to cross the thirdthermal bonding line 133 and thermally bond the two inner sheets 121 toany one of the outer sheets to form an elongated path of air passingthrough the valve 120. Thus, it is possible to prevent air from beingleaked reversely, thereby improving sealing.

The second thermal bonding portion 152 is a thermal bonding regionformed with a greater thickness than the first to fourth thermal bondinglines 131, 132, 133, 134, and the second thermal bonding portion 152 hasa smaller length than a gap between the third thermal bonding lines 133.Here, a space between the second thermal bonding line and the secondthermal bonding portion 152 is a pressurization space 160. The secondthermal bonding portion 152 thermally bonds the two outer sheets 105 andthe two inner sheets 121.

In a state that the two inner sheets 121 are positioned in the two outersheets 105, the air input channel 101 is formed by the first thermalbonding line 131 and the second thermal bonding line 132, positioned inparallel with each other. At this time, the second thermal bonding line132 is formed while passing the heat resistance inks 140 discontinuouslyformed along the inner sheets 121. Also, the first thermal bonding line131 bonds just the two outer sheets 105.

The air input channel 101 is formed along the first thermal bonding line131 and the second thermal bonding line 132 as mentioned above, and oneside of the air input channel 101 is closed and the other side isopened. Air is injected through the other side that is open. Meanwhile,the outer sheet 105 and the inner sheet 121 are bonded by the secondthermal bonding line 132, but regions where the heat resistance inks 140are formed are not bonded.

Also, the second thermal bonding portion 152 is formed to cross thethird thermal bonding line 133 between the second thermal bonding line132 and the fourth thermal bonding line 134. FIGS. 3 and 4 show that thesecond thermal bonding portion 152 is spaced apart from the secondthermal bonding line 132, but not limited thereto. The second thermalbonding portion 152 may also be formed continuously from the secondthermal bonding line 132. The second thermal bonding portion 152 islocated spaced apart from a second thermal bonding portion 152 formed onan adjacent third thermal bonding line 133, thereby forming a secondpassage 125B through which air may be introduced to the air pillar 103.

FIG. 5 is a vertical sectional view taken along the line C-C′, whichillustrates a valve while and after the process of injecting air to theair bag shown in FIG. 4 is executed.

Hereinafter, an air flow while air is injected to the air input channel101 of the air bag is explained with reference to FIG. 5.

As seen from FIG. 5, if air is injected to the air input channel 101formed between the first thermal bonding line 131 and the second thermalbonding line 132 using an air injector, the air is injected along theair input channel 101 to expand the air input channel 101.

If the air input channel 101 is expanded as mentioned above, a gapbetween the two inner sheets 121 is widened, so the air is introducedbeyond the second thermal bonding line 132 into the valve 120 betweenthe third thermal bonding lines 133. As the two outer sheets 105 areexpanded due to the injected air, the inner sheets 121 respectivelybonded and fixed by the first thermal bonding point 141 (see FIGS. 3 and4) are widened in opposite directions, thereby opening a passage throughwhich air may be introduced.

Meanwhile, the air introduced into the valve 120, namely between the twoinner sheets 121, passes through the second passage 125B between thesecond thermal bonding portions 152 (the second passage 125B is notclearly shown in FIG. 5 since FIG. 5 is a vertical sectional view takenalong the line C-C′). After that, the air flows along a path formed bythe fourth thermal bonding line 134 and as a result flows into the airpillar 103 through the valve 120.

The air introduced into the air pillar 103 as mentioned above expandsthe air pillar 103 and increases an inner pressure of the air pillar103. If the air pillar 103 is expanded, the two inner sheets 121 areclosely adhered to any one of the outer sheets thermally bonded by thefourth thermal bonding line 134. At this time, the pressure of air isapplied toward the outer sheet to which the two inner sheets 121 arethermally bonded, thereby closing the valve 120. The air pressure isconcentrated on a curved region formed just below the location of thesecond thermal bonding portion 152, than on a flat portion, therebygiving a primary sealing effect.

If the inner pressure of the air pillar 103 is further increased in thisstate, the air flows into the pressurization space 160 through thesecond passage 125B of the second thermal bonding portions 152. Also,the air introduced into the pressurization space 160 presses the twoinner sheets 121 in the pressurization space 160 toward any one of theouter sheets, thereby giving a secondary sealing effect. Here, the airpressure is more concentrated on a curved region of the outer sheetexpanded by a thermally bonded region, such as a region below the secondthermal bonding line 132 and above the second thermal bonding portion152, than on a flat portion of the expanded outer sheet 105.

It is because the curved region has a larger surface area than the flatportion, so pressure is more greatly applied to the curved region. Thus,sealing is more excellent as there are more curved regions. In thisprinciple, as the valve 120 is expanded by air, the second thermalbonding portion 152 may further improve a sealing property by formingmore curved regions where air pressure is concentrated.

In other words, in the air bag 100, before the air filled in the airpillar 103 passes through the second passage 125B as the second thermalbonding portion 152 is formed, namely below the second thermal bondingportion 152, the two inner sheets 121 are primarily pressed to any oneof the outer sheets for sealing, and then, after the air passes throughthe second passage 125B, the two inner sheets 121 are secondarilypressed to any one of the outer sheets in the pressurization space 160for sealing, thereby giving a double sealing structure. According to thedouble sealing structure, it is possible to minimize leakage of airfilled in the air pillar 103.

FIG. 6 is a perspective view showing another embodiment of an air bagdisclosed herein.

In the air bag 100 of this embodiment, a heat resistance ink 140 iscontinuously applied to an end of an inner side of any one of the twoinner sheets 121 in a length direction of the inner sheet. Also, the airbag 100 further includes a first thermal bonding portion 151 thatensures smooth widening of the valve 120. Here, the length direction ofthe inner sheet means a direction perpendicular to the third thermalbonding line 133, namely a direction perpendicular to a length directionof the air pillar 103.

In detail, the first thermal bonding portion 151 is discontinuouslyformed between the first thermal bonding line 131 and the second thermalbonding line 132 in correspondence to the third thermal bonding line133, and it is formed at an end of the inner sheet coated with the heatresistance ink 140. A part of the first thermal bonding portion 151thermally bonds the two outer sheets 105, and the other part of thefirst thermal bonding portion 151 thermally bonds the two outer sheets105 and the two inner sheets 121. Here, a gap between the first thermalbonding portions 151 is called “a first passage 125A”.

Also, the heat resistance ink 140 is continuously applied to an end ofthe inner sheets 121, and also the second thermal bonding line 132 isformed along the heat resistance ink 140. As the second thermal bondingline 132 is formed along the heat resistance ink 140 as mentioned above,the third thermal bonding line 133 may be connected to any point of thesecond thermal bonding line 132. Also, a gap between the third thermallines 133 is opened due to the heat resistance ink 140, so air may beeasily injected into the air pillar 103 formed by the third thermalbonding line 133.

A method for making the air bag of this embodiment will be explained inmore detail. The two inner sheets 121 are positioned on one outer sheet105, and the fourth thermal bonding line 134 is formed such that the twoinner sheets 121 are fixed to one outer sheet 105. Then, the other outersheet 105 is placed to cover the two inner sheets 121. Here, the heatresistance ink 140 is located at an inner portion of the overlappedinner sheets.

Then, an air input channel 101 is formed. The air input channel 101 ismade by forming the first thermal bonding line 131 and the secondthermal bonding line 132. The first thermal bonding line 131 is formedin parallel along a length direction of the valve 120 just by thermallybonding the two outer sheets 105. The second thermal bonding line 132extends in parallel with the first thermal bonding line 131 continuouslyalong the heat resistance ink 140. At this time, the two inner sheets121 are not bonded to each other due to the heat resistance ink 140, butthe outer sheet 105 is bonded to the inner sheet 121.

In this state, the third thermal bonding line 133, the first thermalbonding portion 151 and the second thermal bonding portion 152 may beformed at the same time by molding or formed in any order according towork conditions. The forming order may be changed.

The third thermal bonding line 133 perpendicularly extends with respectto the second thermal bonding line 132 to form a sealed air pillar 103.Here, the third thermal bonding line 133 formed at a region where theinner sheet 121 is located thermally bonds all of the two inner sheets121 and the two outer sheets 105, and the third thermal bonding line 133formed at a region where the inner sheet 121 is not located thermallybonds only the two outer sheets. The third thermal bonding line 133formed at a region where the heat resistance ink 140 is located bondsonly the inner sheet 121 and the outer sheet 105 due to the heatresistance ink 140 but does not bond the inner sheets 121 with eachother.

Meanwhile, the first thermal bonding portion 151 is formed between thefirst thermal bonding line 131 and the second thermal bonding line 132,namely at the air input channel 101, and the first thermal bondingportion 151 is formed at an end of the inner sheet 121 in correspondenceto the third thermal bonding line 133, namely at an end where the heatresistance ink 140 is applied. Thus, a part of the first thermal bondingportion 151 located at an inner side of the heat resistance ink 140thermally bonds the inner sheet 121 to the outer sheet, and the otherpart of the first thermal bonding portion 151 located at an outer sideof the inner sheet 121 thermally bonds only the outer sheets 105. Here,a gap between the first thermal bonding portions 151 is the firstpassage 125A.

One end of the air input channel 101 is closed, and the other end of theair input channel 101 at an opposite side to the air pillar 103 wherethe valve 120 is positioned is closed. Thus, as air is introduced intothe air pillar 103 through the valve 120, the air pillar 103 isexpanded.

FIG. 7 is a sectional view taken along the line B-B′, which illustratesexpansion of the air introduction channel and widening of the firstpassage by the thermal bonding portion shown in FIG. 6. If the air inputchannel 101 is expanded, the two inner sheets 121 are respectivelybonded to the outer sheet 105 by the first thermal bonding portion 151to widen a gap between the two inner sheets 121, thereby forming thefirst passage 125A. The air is introduced through the first passage 125Aover the second thermal bonding line 132 into the valve 120 between thethird thermal bonding lines 133. While air is introduced through thefirst passage 125A, a direction in which the first passage 125A isexpanded is identical to a direction in which the valve 120, namely thetwo inner sheets 121, is widened. In other words, in this embodiment,the first passage 125A does not form an oval shape in which a major axisis longer than a minor axis, but is widened in a substantially circularshape since the expanding direction of the first thermal bondingportions 151 is identical to the widening direction of the first passage125A. Thus, a pressure applied to the first passage 125A exerts apressure to open the valve 120, so the valve is smoothly opened by thefirst passage 125A.

Components that may be added to the air bag of this embodiment will beexplained in detail.

Thermal bonding points 139 are formed with intervals in a directionperpendicular to the air pillar 103 in the middle of the air pillar 103in its length direction. The thermal bonding points 139 play a role of afolding line along which the air pillar 103 may be folded. At least onethermal bonding point 139 may be formed per one air pillar.Particularly, two or three thermal bonding points 139 may be formed perone air pillar 103.

In a general air bag 10, a folding line 17 is formed in a widthdirection of the air pillar 13. The folding line 17 does not entirelyclose the air pillar 13 such that air may flow in the air pillar 13, butthe folding line 17 reduces an inner space of the air pillar 13, so theair pillar 13 may be easily folded with respect to the folding line 17.This folding line 17 should be positioned at a width center of the airpillar 13. If the folding line 17 leans in one direction, an inner spacein an opposite side is wider, so it is difficult to fold the air pillar13.

However, if the air bag 10 is pushed from its accurate location when thefolding line 17 is formed, the folding line 17 may be frequently biasedin one side, not located at a width center of the air pillar 13.

In accordance with this embodiment, at least one thermal bonding point139 bonded to have a substantially circular shape is formed per one airpillar 103 of the air bag 100. Two thermal bonding points 139 may beformed at regular intervals per one air pillar 103. The thermal bondingpoints 139 are formed in the air pillars 103 without occupying a largearea, differently from a general folding line 17. Thus, even when theair bag 100 is pushed while the thermal bonding points 139 are formed,the inner space of the air pillar 103 may be more uniformly reduced. Inthis way, the air pillar 103 may be easily folded due to the thermalbonding points 139.

FIG. 8 is a plan view showing another embodiment of an air bag disclosedherein, to which a cock is mounted. The air input channel 101 explainedabove has one closed side and the other open side, so an air injector isinserted into the other open side to inject air therein. However, asshown in FIG. 8, it is also possible that both ends of the air inputchannel 101 are closed, but a cock 170 is formed in any one of the outersheets 105 corresponding to the air input channel 101. In this case, anair injector is closely adhered to the cock 170 and then injects airinto the air input channel 101.

INDUSTRIAL APPLICABILITY

The air bag disclosed herein ensures an excellent sealing property andhigh productivity, so it may be used for packaging various articles.

1. An air bag, comprising: two inner sheets positioned to face eachother; two outer sheets respectively located at an outer side of the twoinner sheets; a heat resistance material located at an inner side of thetwo inner sheets and applied to any one of the inner sheets; a firstthermal bonding line for thermally bonding the two outer sheets to forman air input channel; a second thermal bonding line for thermallybonding the inner sheets and the outer sheets along the heat resistancematerial with a gap from the first thermal bonding line; and thirdthermal bonding lines extending from the second thermal bonding line ina direction opposite to the air input channel to form air pillars,wherein a second thermal bonding portion is formed at the third thermalbonding lines in a crossing direction thereof to thermally bond the twoinner sheets and the two outer sheets such that a pressurization spaceis formed between the second thermal bonding portion and the secondthermal bonding line, and the second thermal bonding portion is spacedapart from a second thermal bonding portion extending from anotheradjacent third thermal bonding line to form a second passage.
 2. The airbag according to claim 1, wherein fourth thermal bonding lines with alength smaller than an interval between the third thermal bonding linesextend from the third thermal bonding lines in a lateral direction, andwherein the fourth thermal bonding lines thermally bond the two innersheets to any one of the outer sheets, and the fourth thermal bondinglines are formed at an opposite side to the second thermal bonding linewith respect to the second thermal bonding portion.
 3. The air bagaccording to claim 1, wherein the heat resistance material iscontinuously applied to the inner sheets in a length direction, and thesecond thermal bonding line thermally bonds the inner sheets and theouter sheets along the heat resistance material.
 4. The air bagaccording to claim 1, wherein a plurality of first thermal bondingportions are formed in the air input channel in correspondence to thethird thermal bonding lines, respectively, such that adjacent firstthermal bonding portions are spaced apart from each other to form afirst passage, and wherein a part of the first thermal bonding portionsthermally bond the two outer sheets, and the other part of the firstthermal bonding portions thermally bond the outer sheets to the innersheets.
 5. The air bag according to claim 1, wherein at least onethermal bonding point for thermally bonding the two outer sheets in adirection perpendicular to the air pillars is formed at a middle of eachair pillar in a length direction thereof.
 6. The air bag according toclaim 1, wherein both ends of the air input channel are closed, and acock is formed at any one of the outer sheets corresponding to the airinput channel.